NERVOUS SYSTEM

Considered as a communication system, receiving signals from and sending commands to different areas of the body.

Two major divisions of the nervous system

The Central Nervous System consists of?

The Peripheral Nervous System consists of?

This is the communication link between the CNS and the various parts of the body.

The PNS carries information about the body tissues ___ the CNS and delivers commands ___ the CNS to other body tissues that alter body activities.

The Peripheral Nervous System has two divisions

This means Afferent Division

This means Efferent Division

Meaning “towards”

Meaning “away”

Division of the PNS conducts action potentials from sensory receptors to the CNS

Neurons that transmit action potentials from the periphery to the CNS

Division of the PNS conducts action potentials from the CNS to effector organs

Neurons that transmit action potentials from the CNS to the periphery

The effectors controlled by the motor division include _ and _

This muscle is voluntarily controlled

This muscle is involuntarily controlled

The motor division has 2 components

Transmits action potentials from the CNS to skeletal muscles

Transmits action potentials from the CNS to cardiac muscle, smooth muscle and glands.

The Autonomic Nervous System has two divisions

A unique part of the PNS, has both sensory and motor neurons contained wholly within the digestive tract.

Two types of cells that make up the nervous system

Receive stimuli, conduct action potentials, and transmit signals to other neurons or effector organs.

A neuron has 3 parts:

Each neuron _ contains a single nucleus.

Short, highly branching cytoplasmic extensions that are tapered from their bases at the neuron cell body to their tips.

Extensions of the neuron cell body

A single long cell process extending from the neuron cell body

The area where the axon leaves the neuron cell body

An axon may remain unbranched or may branch to form ___

Axons can be surrounded by a highly specialized insulating layer of cells called the ____

Type of neuron that has many dendrites and an axon

Type of neuron that has an dendrite and an axon

Type of neuron that has an axon and no dendrites.

Example of Multipolar Neuron

Example of Bipolar Neuron

Example of Pseudo- Unipolar Neuron

These are the supportive cells of the CNS and PNS and they do not conduct action potentials

Types of Glial Cells in the CNS

Types of Glial Cells in the PNS

Serve as the major supporting cells in the CNS. Stimulate and inhibit signaling activity of nearby neurons.

Astrocytes participate with the blood vessel endothelium to form a permeability barrier called the ____

Permeability barrier between the blood and the CNS

Cells that line the fluid-filled cavities within the CNS

What are the fluid-filled cavities?

Ependymal cells produce?

This helps the cerebrospinal fluid to move through the CNS

These cells act as the immune cells of the CNS

These cells hell protect the brain by removing bacteria and cell debris in the CNS

These cells provide an insulating material that surrounds axons in the CNS

These cells provide an insulating material around axons in the PNS

Found around the cell bodies of certain neurons of the PNS. These provide support and nutrition to the neurons and protect the neurons from heavy-metal poisons, such as lead and mercury.

Specialized layers that wrap around the axons of some neurons

Myelin sheaths are formed by?

Axons with myelin sheaths are called?

An excellent insulator that prevents almost all ion movement across the cell membrane.

Gaps in the myelin sheath

Lack the myelin sheaths, these axons rest in indentations of the Oligodendrocytes of the CNS and the Schwann cells of the PNS

Nervous tissue exists as

Consists of groups of neuron cell bodies and their dendrites, where there is very little myelin

Gray matter in the CNS

Gray matter of the CNS located on the surface of the brain

Clusters of gray matter located deeper within the brain

Gray matter of the PNS. A cluster of neuron cell bodies

Consists of bundles of parallel axons with their myelin sheaths which are whitish in color

White matter of the CNS which propagate action potentials from one area of the CNS to another

White matter of the PNS consists of bundles of axons and associated connective tissue that form ___

Two basic types of ion channels

Channels that are always open

Channels that are closed until opened by specific signals

Two types of gated channels

Gated channels that are opened by specific chemicals

Gated channels that are opened by a change in the electrical property of the cell membrane